Background and Objectives: Spinal anesthesia is widely used, providing a fast onset and effective sensory and motor blockade. Systemic hypotension and bradycardia are the more common side effects seen during the central neuraxial block. Levobupivacaine has been introduced into clinical practice because of its lower toxic effects for the heart and central nervous system. We, therefore, performed this prospective randomized clinical study to compare the clinical efficacy and hemodynamics of 3 ml of 0.5% intrathecal isobaric Levobupivacaine with 3 ml of 0.5% intrathecal racemic Bupivacaine for lower abdomen and lower limb surgeries. Methodology: 100 patients belonging to ASA physical status I and II scheduled for lower abdomen and lower limb surgeries were randomly selected for the study and were divided into 2 groups of 50 each. Group L (Levobupivacaine group) received 3ml of 0.5% isobaric Levobupivacaine (15mg) intrathecally Group B (Bupivacaine group) received 3ml 0.5% of racemic Bupivacaine (15mg) intrathecally. Onset and duration of sensory block, onset duration and degree of motor block, maximum dermatomal level of sensory block, hemodynamic parameters, and adverse effects if any were studied. Results: There was a statistically significant difference between both the groups with regards to mean onset of sensory and motor block which was significantly faster in group B when compared to group L. The mean time for peak sensory block was 7.44 mins with Levobupivacaine and 6.84 mins with Bupivacaine (p-value 0.02). The mean onset time for the motor block was 10.99 mins with Levobupivacaine and 10.48 mins with Bupivacaine (p-value 0.05). The maximum sensory height attained ranged between T4 and T10 in both the groups, which was clinically and statistically not significant. The mean time for 2 segment regression was 123.8 mins in group L and 126.5 mins in group B which was statistically not significant (p-value 0.23). The degree of motor block was comparable in both groups. The mean duration of sensory block was 257.4 mins in group L and 259.9 mins in group B which was clinically and statistically not significant (p-value 0.17). The mean duration of motor block was 283.2 mins in group L and the group was 286.3 mins with a p-value of 0.31 which clinically and statistically was not significant. Hypotension and bradycardia were less common in group L than group B which was clinically and statistically significant. 52% of patients in group B and 16% of patients in group L required the use of vasopressor with a statistically significant p-value of <0.001. 30% of patients in group B had bradycardia compared to 8% in group L with a p-value of 0.002. The incidences of other side effects were comparable in both the groups. Conclusion: Levobupivacaine 15 mg (3ml of 0.5% Isobaric) has significantly a late onset of sensory and motor block but had a similar duration of sensory and motor block compared to Bupivacaine 15 mg (3ml). However, Bupivacaine required more often the use of a vasopressor and sympathomimetic drug compared to Levobupivacaine. So Levobupivacaine could be advisable inpatient whose clinical history demandsthe cardiovascular impact of spinal anesthesia to be minimized.

Keywords: Levobupivacaine; Bupivacaine; Intrathecal; Isobaric.